1.4 Quiz Cevaplari

1 Which of the following describes frequency?

length of each wave
height of each wave
* number of cycles each second
amount of time between each wave

2 Which of the following describe sine waves? (Choose three.)

They do not continuously vary with time.
* They repeat the same pattern at regular intervals.
* They occur naturally and change regularly over time.
They are artificially created and do not occur naturally.
* No two adjacent points on a graph have the same value.
They have continuously varying patterns that do not repeat.

3 Identify common ways in which the capacities of communication systems are measured? (Choose two.)

analog bandwidth
resistance capacity
carrier bandwidth
polarity capacity
* digital bandwidth

4 Why would fiber optic installations be favored over copper between buildings? (Choose two.)

cheaper installation
larger media
* attentuation properties
* no electrical interference
easier termination and installation

5 How are binary ones and zeros represented in fiber optic installations? (Choose two.)

+5 volts/-5 volts
0 volts/5 volts
* light/no light
high to low electrical transition
low to high electrical transition
* increasing/decreasing light intensity

6 What are some of the factors that contribute to attenuation in a copper media? (Choose three.)

type of voltage used
* long cable lengths
jitter signal sent by the transmitting device
* defective connectors
* energy leaks through the insulation of the cable
low signal frequencies

7 What problems are associated with impedance mismatches in copper cabling? (Choose two.)

* jitter
signal absorption
termination of signals
* reflection
NEXT

8 What conditions are described when transmission signals from one wire pair affects another wire pair? (Choose two.)

* noise
resistance mismatch
jitter
* crosstalk
attenuation

9 What type of wiring problem is depicted in this sample of a cable tester?

a fault
a short
* an open
a split
a good map

10 What factors need to be considered to limit the amount of signal attenuation in long Ethernet cable runs? (Choose two.)

* type of media
number of users
type of users
* length of cable
type of electrical equipment

11 Which of the following are tests specified by the TIA/EIA-568-B standard for copper cable? (Choose three.)

signal harmonics
conductive response
* wire map
signal absorption
* insertion loss
* propagation delay

12 Which of the following describe amplitude?

* the height of each wave
the length of each wave
the number of waves each second
the amount of time between each wave

13 In a new network installation, the network administrator has decided to use a medium that is not affected by electrical noise. Which cable type will best meet this standard?

coaxial
screened twisted pair
shielded twisted pair
unshielded twisted pair
* fiber optic

14 Which of the following are true concerning crosstalk? (Choose three.)

** FEXT is less of a problem than is NEXT.
Using frequency step sizes that are larger than those specified by the TIA/EIA standard has no effect on link fault detection.
** A cable with a NEXT measurement of 30 dB would be considered a better cable than one which has a NEXT measurement of 10 dB.
** NEXT needs to be measured from each pair to each other pair in a UTP link, and from both ends of the link.
FEXT is determined by injecting a signal into a pair of wires and measuring the signal strength on the other end of the same pair of wire.

15 Which frequencies are used by a cable tester to measure attenuation?

the lowest frequencies that the cable is rated to support
* the highest frequencies that the cable is rated to support
frequencies from 20 Hz to 20 kHz in 20 Hz increments
10 kHz and 100 GHz

16 Which of the following are true about square waves? (Choose three.)

* They repeat the same pattern at regular intervals.
They continuously vary with time.
* They represent digital signals.
* They do not continuously vary with time.
They occur naturally and change regularly over time.
They represent analog signals.

17 What is the purpose of shielding in copper based media? (Choose two.)

* protect the data signal from noise generated by electrical signal within the cable
ground the cable and prevent electrical shocks
* protect the data signal from external sources of noise
decrease attenuation and increase the length possible for the cable run
ground the cable so that the zero volt reference point is accurate

18 Why are pulses important in digital communication?

create the timing mechanism for data transmission
* determine the value of the data being transmitted
damage data transmissions
signal collisions in data streams

19 Two wires from different wire pairs are connected to the wrong pins on both ends of a cable. What is the wire fault name for this connection?

open
short
* split-pair
transposed-pair

20 Which of the following are detected by the wire map test? (Choose three.)

near-end crosstalk (NEXT)
* opens
propagation delay
return loss
* reversed-pair faults
* short circuits

21 Which one of the following cable tests verifies that all eight wires are connected to the correct pins on both ends of the cable?

cable length
insertion loss
near-end crosstalk (NEXT)
propagation delay
return loss
* wire map test

22 To ensure reliable LAN communications, what should a technician be looking for when attaching connectors to the ends of UTP cable?

that the white-orange/orange pair is attached first
* that the wire pairs remain twisted as much as possible
that one end of the shield is properly ground but not the other
that 50 ohm termination resistors are on both ends

23 What types of shielding are used in shielded twisted-pair (STP) cable? (Choose two.)

insulating material
lexan infused
* braided conductive
* foil-screened
rubber molding
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